Maintenance for the week of March 25:
• [COMPLETE] ESO Store and Account System for maintenance – March 28, 9:00AM EDT (13:00 UTC) - 12:00PM EDT (16:00 UTC)
Might have something to do with the time change.
I know Apple seems to have alarm issues every time the clocks change so maybe they just want to make sure no one logs in right when their device is updating the time..
Earlier today there were some issues affecting the ESO servers on all platforms that led to login issues for a short time. This issue is now resolved and players should be able to log back in.